Arrangement for mounting components on a carrier board and method of indicating mounting locations

ABSTRACT

The mounting locations for .[.separable.]. insertion of components on a printed circuit board are indicated by a projected luminous .[.spot which is moved sequentially and repeatedly between the several mounting spots for each component. The direction of movement of the luminous dot is changed in each mounting spot..]. dot which moves from one mounting spot to the next to indicate the array of mounting spots forming the mounting location. The movement is cyclically repeated in the same sequence to indicate to the installer the mounting location. Thereafter the luminous dot is moved to the next mounting location and the same cyclical and sequential scanning is repeated. The spot travels over the board in response to an element of the optical system in the projector being moved in a plane parallel to the board surface under control of a programmed unit.

.Iadd.This application is a continuation of application Ser. No.06/290,546 filed 08/06/81, now abandoned, which is a reissue ofapplication Ser. No. 05/851,830 filed 11/16/77, now patent No.4,163,309..Iaddend.

This invention relates to the assembly of circuit boards with separablecomponents, and particularly to a method of indicating mountinglocations for the components, wherein each location includes a pluralityof mounting spots, and to an arrangement for mounting such components oncircuit boards.

It is known to indicate mounting positions on a circuit board by meansof a projected luminous arrow. The length and direction of the arrow inthe known indicating method can be varied to indicate size andorientation of the component to be mounted. The arrow stands still andmay not be detected easily in a brightly lit room and or amongpreviously mounted components of the board.

An important object of the invention is the provision of a method whichindicates a mounting location and the several spots of a mountinglocation in a manner more readily visible even under unfavorablelighting conditions.

Another object is the provision of a mounting arrangement capable ofperforming the method and of otherwise facilitating the mountingoperation.

It has been observed that a moving luminous dot is more readily detectedthan stationary luminous indicia of equal luminosity, and as has beenfound that dimensions and orientation of a component to be mounted arereadily indicated by the distance over which the luminous dot travels.

The invention, in one of its more specific aspects, resides in a methodof indicating at least one mounting location including a plurality ofmounting spots spaced on a surface, which method comprises projecting aluminous dot on the surface, moving the projected dot sequentially andrepeatedly between the mounting spots to be indicated, and changing thedirection of movement of the dot in each of the spots.

In another aspect, the invention resides in an arrangement for mountingcomponents on a surface of a carrier board in which the carrier board issecured on a support in a precisely defined position. A projectorincludes an optical system of projecting a luminous dot on the surfaceof a secured carrier board. Means are provided for moving an element ofthe optical system in a plane parallel to the surface of the board, anda control unit controls the movement of the optical element in apredetermined sequence.

Other features, additional objects, and many of the attendant advantagesof this invention will readily be appreciated as the same becomes betterunderstood from the following detailed description of a preferredembodiment when considered in connection with the appended drawing inwhich:

FIG. 1 illustrates a projector of the invention projecting luminousindicia on a circuit board and an associated control system infragmentary perspective view, partly in section, and by conventionalsymbols;

FIG. 2 is a top plan view of elements of the projector of FIG. 1 and ofan associated component supply unit; and

FIG. 3 is a fragmentary top plan view of the supply unit of FIG. 2without a portion of its housing but with associated drive elementsconnected to the control system of FIG. 1.

Referring initially to FIG. 1, there is shown a projector 10 on whosebaseboard 11 a carrier board 12 for electrical components, such as aprinted circuit board is precisely positioned by means of four,threaded, locating pins 13. A luminous dot 14 having a diameter ofpreferably 2.3 mm, but generally 1 to 3 mm diameter, is projected by theoptical system of the projector 10 whose externally visible partsinclude a lamp housing 16 mounted on the baseboard 11 by means of abracket 15 and a column, not shown, and a lens barrel 18 independentlymounted as will presently be described.

The optical system of the projector 10 includes a point light source 20,such as an incandescent electric lamp, a condenser lens 22, an apertureplate 24, and an objective lens system 26. A portion of the housing 15spherically curved about the aperture in the plate 24 is movablyreceived in a circular opening of the bracket 15 so as to provide auniversal joint for tilting movement of the housing 16 in alldirections. The beam of light from the lamp 20 is confined in a flaringtube 28 fixedly attached to the housing 16 and received with ampleradial clearance in an axially overlapping cylindrical tube 30 attachedto the lens barrel 18.

The barrel may be moved in a plane parallel to the surface of thecircuit board 12 by two electric stepper motors 32 and associated wormgears, the worms being journaled at right angles to each other in thesupporting structure of the projector and carrying the lens barrel 18.Only one motor 32 is shown in the drawing together with a controlcounter 34 which incidates the position of the spot 14 in the directionof the X-axis, the movement of the lens barrel 18 in the direction ofthe Y-axis being caused by another, identical motor obscured in the viewof FIG. 1, and equipped with a counter.

Conductors 33,35 connect the motors to the operating unit 40 of acontrol system 36 also including a program storage unit 38 and aprogramming unit 42. A lever 44 mounted on the programming unit 42 forpivotal manual movement about two perpendicularly intersecting axespermits the spot 14 to be shifted by the operating unit 40 and theconnected motors 32 to a desired location on the surface of the circuitboard 12, and the location as indicated on the counters 34, may then beentered in the program storage unit 38 by pressing a key 46.

The program storage unit 38 may be provided with interchangeableprograms, preferably based on CMOS semi-conductor storage and may have acapacity of 4 to 32,000 bits, the larger number being adequate forindicating the location of up to 700 components.

The operating unit 40 includes a non-illustrated comparator which is fedactual location signals from the counters 34 and nominal locationsignals from the storage unit 38 to produce an error signal whichactuates the motors 32 in the necessary manner to minimize thedifference.

After entry of coded information on two spots 50,52 spaced apart adistance a in the X direction by means of the lever 44 and the key 46,as described above, additional, equally spaced spots 54,56 may beentered in the storage unit 38 by manually entering the spot 54, andthereafter pressing one of four direct-setting keys 48, whereupon thespot 56 is entered automatically. The control system 36 is normallyline-operated, but may be provided with a back-up battery for protectionagainst line failure.

Adjusting keys 51 in the operating unit 40 permit adjusting the unit forinaccurate positioning of the circuit board 12 on the projectorbaseboard 11. A stepping key 53 on the operating unit 40 causes the dot14 to be shifted to the next mounting location.

As is shown in FIG. 2, the baseboard 11 of the projector 10, nototherwise illustrated in FIG. 2, is fastened centrally to therectangular cover 92 of a supply unit 58 for the components to bemounted on the baseboard 12. The supply unit is shown in FIG. 3 withoutmuch of its housing which encloses 16 elongated bings or receptacleslongitudinally divided into the three equal compartments 61. The bins 60travel on caster-mounted carriers, not shown, in rectangular,loop-shaped paths having sections extending in the direction of arrows62 transversely to the common direction of elongation of the bins 60 andthe unit 58, and longitudinal sections in the direction of arrows 64.The bins 60 are moved on the bottom wall 66 of the housing in thedirection of the arrows 64 by engagement with dogs 67 on a drive chain68 which envelops the paths of the bins 60. The bins are movedtransversely away from the chain 68 by projections 72 on two-armedrockers 70 pivotally mounted on the bottom wall 66 and engaging ribs 74on the underside of each bin carrier between the nonillustrated casters.A 180° turn of a rocker 70 shifts a bin 60 away from the chain 68 by itsown width, thereby further shifting the farthest one of a column ofthree previously shifted bins into the path of the chain 68.

The chain 68 travels in a rectangular loop over four guide pulleys ofwhich at least one is driven by a reversible motor 69 through aunidirectional clutch 73. The eight rockers 70 are driven by the samemotor 69 through another unidirectional clutch 71. The motor 69 isenergized intermittently, and its direction of rotation is controlled bythe operating unit 40 in a synchronization with the motors 32. When themotor 69 rotates forward the chain 68 is driven until the four bins 60engaged by the dogs 67 in the position of FIG. 3 advance byapproximately 1/3 of a bin length, and they are aligned in the directionof the arrows 62 with respective horizontal stacks of three bins afterthe next step in the same direction. When the motor 69 is energized torotate backward, only the clutch 71 transmits motion to the rockers 70which are turned 180° and shift the leading four bins of the respectivestacks into positions of engagement with the chain 68.

As is seen in FIG. 2, an opening 94 in the cover 92 gives access to onecompartment of a bin 60 stopped thereunder during its movement in thedirection of an arrow 64 to present to an operator the component neededfor mounting in one location of the board 12, the several terminals ofthe component being attached to respective receiving terminals in theseveral mounting stops at the location indicated. When the operator nextpushes the key 53, the access opening 94 is temporarily closed by asafety cover 96 in a known manner, not specifically illustrated, whilethe bin 60 advances by the length of one compartment, and the lensbarrel 18 is shifted to indicate the next mounting location. As soon asthe chain 68 stops, the cover 96 gives access to a supply of thecomponent to be mounted at the newly indicated location.

A hinged door 98 in the cover 92 permits the contents of the bins 60 tobe replenished as may be needed, or to be replaced by other componentsif different circuit boards are to be assembled. The program no longersuitable for the different assembly operation may be replaced quickly inthe unit 38 in a manner known in itself. A read-out 90 on the operatingunit 40 may indicate the serial number of the bin compartment 61 alignedwith the access opening 94 and may also be utilized for signalingapproaching exhaustion of the component supply in the aligned bin.

While the luminous dot 14 indicates the mounting spots 50,52 for the twoterminals of a component, such as a resistor or capacitor, it is causedby the program stored in the unit 38 to move back and forth between thetwo spots. It has been found advantageous to stop the dot at each pointof reversal for a period of not less than 0.05 nor more than one second,a dwell time of approximately 0.2 seconds being usually long enough toidentify the mounting spot safely without slowing the operator.Visibility of the dot is increased by varying its luminous intensityduring the dwell times as by alternatingly turning it on and off. Thespeed of dot travel between the spots 50,52 may be selected at will. Atraveling speed as high as 30 cm/sec. is entirely feasible. Preferably,the dot should scan all mounting spots of the location ofr a componentwithin 0.4 to one second, the actual travel time depending less on thedistance of the individual spots than on the number of spots. Four spots78, 80, 82, 84 may be scanned sequentially in repeated cycles nearer theupper limit of one second than two spots associated with the samemounting location. During travel from one spot to the other within thesame mounting location, the dot may be turned off completely. Whentraveling from the spots 78-84 to a spot 86 at another mountinglocation, the dot should preferably be bright enough to be visible tothe operator. For the comfort of the operator, the dot should travel notfaster than approximately 30 cm/sec. to guide the eyes of the operatorwithout conscious effort.

When the distance traveled by the dot 14 exceeds a certain maximumvalue, the correspondingly moved lens barrel 18 causes the cylindricaltube 30 to engage a flaring skirt at the free end of the tube 28 andthereby to tilt the lamp housing 16 at about the aperture in the plate24 to maintain adequate luminosity of the dot 14 without impairing thesharp definition of the dot. The tube 30 and tube 28 thus constitute alost-motion coupling which does not become effective as long as theobjective moves within a relatively narrow range. The light source thusdoes not participate in the quick and short movements of the lens barrelwhile the dot travels between the several spots of a mounting location,and the life of its filament is greatly lengthened thereby.

It should be understood, of course, that the foregoing disclosurerelates to a preferred embodiment, and that it is intended to cover allchanges and modifications of the example of the invention herein chosenfor the purpose of the disclosure which do not constitute departuresfrom the spirit and scope of the invention set forth in the appendedclaims.

I claim:
 1. A method of indicating at least one mounting location.[.including.]. .Iadd.for a component, by identifying .Iaddend.aplurality of mounting spots spaced on a surface .Iadd.onto which thecomponent is to be mounted, .Iaddend.which comprises:(a) projecting aluminous dot on said surface; (b) moving the projected dot.Iadd.continuously and without cessation of projection during suchmovement .Iaddend.sequentially .Iadd.among at least two said mountingspots; .Iaddend.and .[.repeatedly between the mounting spots to beindicated;.]. (c) .[.changing the direction of movement of said dot ineach of said spots. .Iadd.cyclically repeating said sequential movementof said dot for indicating at least one said mounting location..Iaddend.2. A method as set forth in claim 1, wherein the movement of said dot isstopped in each of said spots for a dwell time of 0.05 to 1 second.
 3. Amethod as set forth in claim 1, wherein the diameter of said dot isbetween 1 and 3 millimeters.
 4. A method as set forth in claim 3,wherein the movement of said dot is stopped in each of said spots for adwell time of 0.05 to 1 second.
 5. A method as set forth in claim 3,wherein the luminous intensity of said dot is modulated cyclicallyduring said dwell time.
 6. A method as set forth in claim 1, wherein theluminous intensity of said dot is reduced during movement between saidspots.
 7. A method as set forth in claim 1 wherein two of said mountinglocations are to be indicated, said dot after said moving over themounting spots of said one location being moved from said one locationto the other location while maintaining a luminosity perceptible to thehuman eye. .Iadd.
 8. A method of indicating at least one mountinglocation among a plurality of mounting spots spaced on a surface ontowhich the component is to be mounted which comprises:(a) projecting aluminous dot on said surface; (b) moving said projected dot continuouslyand without cessation of projection during such movement back and forthbetween two said mounting spots for indicating at least one saidmounting location..Iaddend. .Iadd.
 9. Arrangement for producing anindication of the location of a particular component for a support boardto be equipped with electrical components whereby a circuit-board ispositioned within a support and adjusted by adjusting means and wherebythe indication is obtained by superposition of a lightpoint and thesupport board whereby the lightpoint at least during a fraction of theindicating period can be displaced in such a way, that the timedependent changeable positions of the lightpoint mark locations(terminals) on the support board to be connected electrically andwhereby the lightpoint can be modulated with regard to its luminosity,the arrangement consisting of a moveable projector for producing alightpoint, a drive for the projector for moving the lightpoint alongits path with terminal locations and/or changes of directions as well asa control unit for this drive being provided with a program memory forcontrolling the movement of the projector and an advance keycharacterized in that the program memory (38) for controlling themovement of the projector (10) is arranged;for the repetitive movementsof the lightpoint (14) on the support board (12) and moveable within itsplane between points (terminals) (78-84) of the location (76) ofparticular circuit element to be placed said movement of the lightpointbeing continuous and without cessation of projection during suchmovement; for emphasis of a particular connecting point (terminal) ofthis location (76) by modulation of the lightpoint (14) on thisparticular connecting point as well as; and for switching the lightpointfrom one location of a circuit element to be placed to the next and thaton activation of the advance key (53) the control unit produces anadvance of the lightpoint (14) from one location of circuit element tobe placed to the next..Iaddend. .Iadd.10. Arrangement for producing anindication of the location of a particular electronic component on acircuit board to be equipped with electrical components by identifying aplurality of mounting spots spaced on the circuit board comprising thefollowing steps: positioning a circuit board within a support; adjustingsaid circuit board within said support; projecting a luminous dot onsaid circuit board; moving the luminous dot continuously and withoutcessation of projection during such movement sequentially among at leasttwo said mounting spots by having the luminous dot being produced from amoveable projector which has a drive attached thereto for moving theluminous dot along its path; said projector being guided by a controlunit having a program memory for controlling the movement of saidprojector, said program memory being changeable by an advance key;cyclically repeating said sequential movement of said dot for indicatingat least one mounting location..Iaddend. .Iadd.11. A method forindicating at least one mounting location for a component, byidentifying a plurality of mounting spots spaced on a surface, whichcomprises: projecting a luminous dot on said surface; moving saidprojected luminous dot continuously and without cessation of projectionduring such movement sequentially among at least two said mountingspots; modulating the luminous intensity of said luminous dot at one ofsaid mounting spots; and cyclically repeating said sequential movementand modulation of said dot for indicating at least one said mountinglocation..Iaddend.